Thermal stability and bonding in the silver complexes of ethylenediaminetetraacetic acid

The solid silver-EDTA complexes AgH3Y·(3/4)H2O; Ag2H2Y; Ag3HY and Ag4Y·(1/2)H2O (Y−4 is ethylenediaminetetraacetate anion) obtained by reaction of the Ag+ ions with sodium salts of EDTA in different degrees of neutralization in aqueous media have been characterized by means of potentiometric titrations, IR spectrometry, elemental analysis and powder X-ray diffraction (XRD). Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC) were used to investigated the thermal stability of the complexes as well as the decomposition pathways. The thermoanalytical results associated with infrared data lead to the conclusion that the silver-carboxylate group bonding is primarily ionic.